He is widely known as the fastest sidearmpitcher in baseball history (outside of American pitcher, Joe Warbis) who can throw a 160&nbsp;km/h (99.4&nbsp;mph) four-seam fastball. His signature pitch is his two-seam fastball which, due to its unique tailing movement has earned its nickname "Serpant fastball()". His other pitches include a high 70s slider with a sharp horizontal break, a mid 80s forkball, and a rarely used slow-curveball. He is one of the rare pitchers who can and does pitch in multiple pitching forms, freely pitching primarily sidearm and underhand, rarely low three-quarters at will.

Though predominantly known as a closer, Lim was converted to a starting pitcher in 2001, and spent three years as the Samsung Lions' starter before returning to the bullpen in 2004. There was interest from Major League squads but Lim decided to stay in South Korea.